Struct kas::widgets::ScrollBar

pub struct ScrollBar<D = Direction>
where
    D: Directional,
{ /* private fields */ }

A scroll bar

Scroll bars allow user-input of a value between 0 and a defined maximum, and allow the size of the grip to be specified.

Messages

On value change, pushes a value of type ScrollMsg.

Layout

It is safe to not call size_rules before set_rect for this type.

Implementations

impl<D> ScrollBar<D>

where D: Directional + Default,

pub fn new() -> ScrollBar<D>

Construct a scroll bar

Default values are assumed for all parameters.

impl ScrollBar<Down>

pub fn down() -> ScrollBar<Down>

Construct a scroll bar (vertical)

Default values are assumed for all parameters.

impl ScrollBar<Right>

pub fn right() -> ScrollBar<Right>

Construct a scroll bar (horizontal)

Default values are assumed for all parameters.

impl<D> ScrollBar<D>

where D: Directional,

pub fn new_dir(direction: D) -> ScrollBar<D>

Construct a scroll bar with the given direction

Default values are assumed for all parameters.

pub fn direction(&self) -> Direction

Get the scroll bar’s direction

pub fn set_invisible(&mut self, invisible: bool)

Set invisible property

An “invisible” scroll bar is only drawn on mouse-hover

pub fn with_invisible(self, invisible: bool) -> ScrollBar<D>

Set invisible property (inline)

An “invisible” scroll bar is only drawn on mouse-hover

pub fn with_limits(self, max_value: i32, grip_size: i32) -> ScrollBar<D>

Set the initial page length

See ScrollBar::set_limits.

pub fn with_value(self, value: i32) -> ScrollBar<D>

Set the initial value

pub fn set_limits(&mut self, max_value: i32, grip_size: i32) -> Action

Set the page limits

The max_value parameter specifies the maximum possible value. (The minimum is always 0.) For a scroll region, this should correspond to the maximum possible offset.

The grip_size parameter specifies the size of the grip relative to the maximum value: the grip size relative to the length of the scroll bar is grip_size / (max_value + grip_size). For a scroll region, this should correspond to the size of the visible region. The minimum value is 1.

The choice of units is not important (e.g. can be pixels or lines), so long as both parameters use the same units.

Returns Action::REDRAW if a redraw is required.

pub fn max_value(&self) -> i32

Read the current max value

See also the ScrollBar::set_limits documentation.

pub fn grip_size(&self) -> i32

Read the current grip value

See also the ScrollBar::set_limits documentation.

pub fn value(&self) -> i32

Get the current value

pub fn set_value(&mut self, cx: &mut EventState, value: i32) -> bool

Set the value

Returns true if the value changes.

Trait Implementations

impl<D> Clone for ScrollBar<D>

where D: Clone + Directional,

fn clone(&self) -> ScrollBar<D>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<D> Debug for ScrollBar<D>

where D: Debug + Directional,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<D> Default for ScrollBar<D>

where D: Default + Directional,

fn default() -> ScrollBar<D>

Returns the “default value” for a type.

impl<D> Events for ScrollBar<D>

where D: Directional,

fn handle_event( &mut self, cx: &mut EventCx<'_>, _: &<ScrollBar<D> as Widget>::Data, event: Event ) -> IsUsed

Handle an Event

fn handle_messages( &mut self, cx: &mut EventCx<'_>, _: &<ScrollBar<D> as Widget>::Data )

Handler for messages from children/descendants

fn handle_hover(&mut self, cx: &mut EventCx<'_>, _: bool) -> IsUsed

Mouse focus handler

fn steal_event( &mut self, _: &mut EventCx<'_>, _: &<ScrollBar<D> as Widget>::Data, _: &Id, _: &Event ) -> IsUsed

Potentially steal an event before it reaches a child

fn make_child_id(&mut self, index: usize) -> Id

Make an identifier for a child

fn configure(&mut self, cx: &mut ConfigCx<'_>)

Configure self

fn configure_recurse(&mut self, cx: &mut ConfigCx<'_>, data: &Self::Data)

Configure children

fn update(&mut self, cx: &mut ConfigCx<'_>, data: &Self::Data)

Update self using input data

fn update_recurse(&mut self, cx: &mut ConfigCx<'_>, data: &Self::Data)

Update children

fn navigable(&self) -> bool

Is this widget navigable via Tab key?

fn handle_scroll( &mut self, cx: &mut EventCx<'_>, data: &Self::Data, scroll: Scroll )

Handler for scrolling

impl<D> Layout for ScrollBar<D>

where D: Directional,

fn size_rules(&mut self, sizer: SizeCx<'_>, axis: AxisInfo) -> SizeRules

Get size rules for the given axis

fn set_rect(&mut self, cx: &mut ConfigCx<'_>, rect: Rect)

Set size and position

fn find_id(&mut self, coord: Coord) -> Option<Id>

Translate a coordinate to an Id

fn draw(&mut self, draw: DrawCx<'_>)

Draw a widget and its children

fn as_layout(&self) -> &dyn Layout

Get as a dyn Layout

fn id_ref(&self) -> &Id

Get the widget’s identifier

fn rect(&self) -> Rect

Get the widget’s region, relative to its parent.

fn widget_name(&self) -> &'static str

Get the name of the widget struct

fn num_children(&self) -> usize

Get the number of child widgets

fn get_child(&self, index: usize) -> Option<&dyn Layout>

Access a child as a dyn Layout

fn nav_next(&self, reverse: bool, from: Option<usize>) -> Option<usize>

Navigation in spatial order

fn find_child_index(&self, id: &Id) -> Option<usize>

Find the child which is an ancestor of this id, if any

fn translation(&self) -> Offset

Get translation of children relative to this widget

impl<D> Widget for ScrollBar<D>

where D: Directional,

type Data = ()

Input data type

fn as_node<'a>( &'a mut self, data: &'a <ScrollBar<D> as Widget>::Data ) -> Node<'a>

Erase type

fn for_child_node( &mut self, data: &<ScrollBar<D> as Widget>::Data, index: usize, closure: Box<dyn FnOnce(Node<'_>) + '_> )

Call closure on child with given index, if index < self.num_children().